Replatformed a multi-client call-tracking setup from CallRail to Twilio in three weeks.
Replatformed a multi-client call-tracking and routing setup off CallRail and onto Twilio — cheaper, more flexible, and without a single dropped call on cut-over day.
- — Role
- Solo engineer + migration lead
- — Year
- 2024
- — Duration
- ~3 weeks
- — Stack
- Twilio · TwiML Bins · Node.js · Postgres · Retool
-
Day 1
— cost savings
-
0
— dropped calls at cut-over
-
per-client
— routing flexibility
The brief
Lasting SEO is a marketing agency whose clients live and die by inbound calls. CallRail had been the call-tracking backbone for years — but the bill kept climbing, the per-client customisation was rigid, and Will could see the ceiling.
The question wasn’t whether to leave CallRail. It was: can we leave without anyone getting hurt?
What I built
A Twilio-backed call-routing and tracking stack, designed around Lasting SEO’s actual client mix:
- Per-client routing trees (greet, route, record, transcribe) defined as data, not code.
- A migration runbook that cut clients over one at a time, in low-traffic windows, with a rollback path measured in seconds.
- A thin internal admin (Retool) so the ops team could onboard a new client without an engineer.
- Cost dashboards so Will could see the savings in real time, not wait for the invoice.
What changed
Costs dropped on day one. The agency kept (and quietly expanded) its per-client routing flexibility. And — what Will mentioned in the testimonial above — the team came out of the migration more trusting of the system, not less. No drama. No “we’ll watch it for a few weeks.”
What it looked like from the inside
Migrations are scary because they’re unsexy and unforgiving. The best ones are boring, and that’s what we aimed for. Communicate early, cut over slowly, and treat every client’s number as if it were the only one.
“Lachlan led our CallRail to Twilio migration with the kind of calm, methodical clarity that just makes you trust the call. The savings hit immediately, and we kept the per-client flexibility without the complexity I'd braced for.”